While the super-fight between Floyd Mayweather and Conor McGregor is set to take place in less than two weeks, the biggest bout in 2017 between two actual boxers is just a month away. Gennady “GGG” Golovkin and Canelo Alvarez will face off on Sept. 16 in a matchup that could go either way.

Golovkin opened as the slight favorite when the middleweight fight was first announced, though his betting odds have seen a small change in the last few months. Once a -160 favorite at Las Vegas sportsbooks, Golovkin’s odds are down to -150 at the Westgate Las Vegas SuperBook, with Alvarez being a +130 underdog.

The betting odds at online sportsbooks favor Golovkin a little more, according to OddsShark. The undefeated 160-pound champ is either a -155 favorite or a -160 favorite on a few betting websites.

Alvarez finds himself in an unfamiliar position as the underdog, having gone undefeated since suffering his first-ever loss to Floyd Mayweather on Sept. 14, 2013.

“I really don’t think about that,” Alvarez told International Business Times earlier this summer. “I don’t worry about that. I’ve probably been the favorite in most of my fights, but I really don’t pay any mind to that. What I worry about is being in shape, being trained at 100 percent and being ready for the fight.”

Canelo Alvarez, pictured at The Theater at Madison Square Garden on June 20, 2017 in New York City, is the betting underdog in his fight against Gennady Golovkin. Photo: Getty Images

A 23-year-old Alvarez entered his fight with an undefeated Mayweather as a +220 underdog. He’s followed up that majority decision loss with seven straight victories, winning as the favorite in every fight.

Before winning a unanimous decision against Julio Cesar Chavez Jr. on May 6, Alvarez was a -460 favorite. The Mexican fighter had -1200 odds against Liam Smith eight months earlier, and he had -500 odds to beat Amir Khan in May 2016.

Alvarez has been dominant during his winning streak, adding four more knockouts to his resume. Thirty-four of his 49 wins have come via knockout, and there’s a chance Alvarez’s fight with Golovkin won’t last very long.

For all of Alvarez’s power, Golovkin is known as the bigger puncher. Before he went the distance in his most recent win against Daniel Jacobs, GGG had knocked out 23 straight opponents.

“I don't think they're underestimating my power. I think both the fans know and you guys know that the styles, we both have attractive styles,” Alvarez said on a media conference call last week. “And we're both going to fight a fight where anybody can win by knockout. We both have the power to win by knockout. But that's what makes for a great fight, and I think that's what makes it an attractive fight for the fans.”

It hasn’t gotten the same kind of attention that Mayweather vs. McGregor has generated, but Golovkin vs. Alvarez will undoubtedly end up being one of the biggest fights in boxing history. Oscar De La Hoya told IBT that he definitely believes the fight will surpass the 2.2 million buys that Alvarez and Mayweather generated four years ago, and that bout ranks third all-time in terms of PPV sales.